108 South Park St
Yet another great local spot with very reasonable prices. You can get a 3 course dinner here (an appetizer, entree and dessert) for under $40 which is pretty much a steal for SF. Yes, this is another out of the way spot so keep that in mind. As far as the food, I really think this is just as good as some of the more basic places along the tourist paths. They had mussels that were pretty to die for on my last visit.